INTRODUCTION
Aging of the periorbital skin and midface is a complex, dynamic, and three-dimensional process. Studies have demonstrated that the eyes are among the first visual cues to infer age, which is why many patients seek lower eyelid rejuvenation to correct the “tired” look. A youthful periocular region is characterized by minimal wrinkles, no excess skin, fullness, minimal pigmentation, and a smooth lid-cheek transition.1 The peri-ocular skin has the thinnest epidermis and dermis, making it susceptible to cutaneous changes that come with age, highlighted by the fact that this skin is juxtaposed to thicker cheek skin. These changes, such as dermal atrophy and rhytides, are intimately associated with the activity of the orbicularis oculi muscle, making it more susceptible to fine lines and static wrinkles. Periorbital aging is multifactorial and is influenced by alterations in the skin, muscle resting tone, fat, ligaments, and bones.
Young skin is made of 80% type I and 15% type III collagen.2 With age, fibroblasts reduce their type I and type III collagen production, leading to a shift in the collagen ratio and a higher proportion of type III collagen.3 In addition to decreased collagen production, aging skin has more elastin fragments, decreased vascular supply, and flattening of the dermal-epidermal junction.1 Resting muscle tone is another essential component in periorbital aging. It increases with time, leading to dynamic and static rhytids as the orbicularis oculi muscle attempts to find a resting tone on an orbit that is gradually resorbing.
With time, midfacial fat pads descend with downward traction on the arcus marginalis, which leads to volume loss at the inferior orbital rim.1 Facial retaining ligaments are stretched with age, leading to alteration of the periorbital appearance. These facial retaining ligaments serve as anchoring points for the superficial musculoaponeurotic system (SMAS) and overlying dermis to the deep fascia and periosteum.4 These ligaments stabilize the facial fat pads, but continuous muscular activity leads to soft tissue displacement with ligament stretching.
The infraorbital hollow is anatomically divided into four main areas: 1) tear trough groove (TT), 2) nasojugal groove (NJG), 3) palpebromalar groove (PMG), and 4) mid-cheek groove (MCG).5
The tear trough-orbicularis retaining ligament complex is crucial in the undereye aging process. TT ligament is osteocutaneous, and its main function is to tether the orbicularis oculi muscle and malar fat pad to the maxilla. TT continues medially and transitions to becoming the orbital-retaining ligament (ORL) at the mid-pupillary line.5 It can atrophy with time, resulting in infraorbital hollows. The ORL attaches the orbicularis oculi muscle to the orbital rim and forms the superior border of the suborbicularis orbital fat pad (SOOF).5
Lastly, the midface’s vertical and horizontal bony projections are lost with aging. An increase in the vertical height of the orbit and loss of maxillary bony projection lead to decreased surface area available to support the overlying soft tissue. This anatomic change is called the Concertina effect.1 To correct the aging lower eyelid, it is essential to address the skin quality and reinforcement of the attenuated orbicularis oculi muscle and orbital septum.
Filler injections are gaining more popularity for the rejuvenation of the lower eyelid and remain the most challenging area for filler injections. Since the skin is the thinnest under the eyes and it is intimately associated with the orbicularis oculi muscle, adding volume with fillers comes with the inherent risk of product aggregation and the Tyndall effect. Hyaluronic acid (HA) fillers are currently the most commonly used product for infraorbital volume loss correction.6 Other products used for the treatment of the infraorbital area include calcium hydroxyapatite and Poly-L-lactic acid (PLLA).
Poly-L-lactic acid (PLLA) (Sculptra®, Galderma Laboratories, Fort Worth, TX) is a biostimulatory agent, currently FDA cleared for HIV lipoatrophy and correction of fine lines and wrinkles in the cheek area. Multiple studies have shown that it increases type I collagen production 3 to 6 months after injection. PLLA particles are mixed with sterile water, which is absorbed within a few hours of injection, leaving behind the PLLA molecules. The body recognizes PLLA as a foreign body and induces a subclinical macrophage-driven inflammatory reaction, which leads to fibroblast activation and increased collagen synthesis.7 PLLA has numerous off-label indications and is commonly used to address both volume loss and skin
Young skin is made of 80% type I and 15% type III collagen.2 With age, fibroblasts reduce their type I and type III collagen production, leading to a shift in the collagen ratio and a higher proportion of type III collagen.3 In addition to decreased collagen production, aging skin has more elastin fragments, decreased vascular supply, and flattening of the dermal-epidermal junction.1 Resting muscle tone is another essential component in periorbital aging. It increases with time, leading to dynamic and static rhytids as the orbicularis oculi muscle attempts to find a resting tone on an orbit that is gradually resorbing.
With time, midfacial fat pads descend with downward traction on the arcus marginalis, which leads to volume loss at the inferior orbital rim.1 Facial retaining ligaments are stretched with age, leading to alteration of the periorbital appearance. These facial retaining ligaments serve as anchoring points for the superficial musculoaponeurotic system (SMAS) and overlying dermis to the deep fascia and periosteum.4 These ligaments stabilize the facial fat pads, but continuous muscular activity leads to soft tissue displacement with ligament stretching.
The infraorbital hollow is anatomically divided into four main areas: 1) tear trough groove (TT), 2) nasojugal groove (NJG), 3) palpebromalar groove (PMG), and 4) mid-cheek groove (MCG).5
The tear trough-orbicularis retaining ligament complex is crucial in the undereye aging process. TT ligament is osteocutaneous, and its main function is to tether the orbicularis oculi muscle and malar fat pad to the maxilla. TT continues medially and transitions to becoming the orbital-retaining ligament (ORL) at the mid-pupillary line.5 It can atrophy with time, resulting in infraorbital hollows. The ORL attaches the orbicularis oculi muscle to the orbital rim and forms the superior border of the suborbicularis orbital fat pad (SOOF).5
Lastly, the midface’s vertical and horizontal bony projections are lost with aging. An increase in the vertical height of the orbit and loss of maxillary bony projection lead to decreased surface area available to support the overlying soft tissue. This anatomic change is called the Concertina effect.1 To correct the aging lower eyelid, it is essential to address the skin quality and reinforcement of the attenuated orbicularis oculi muscle and orbital septum.
Filler injections are gaining more popularity for the rejuvenation of the lower eyelid and remain the most challenging area for filler injections. Since the skin is the thinnest under the eyes and it is intimately associated with the orbicularis oculi muscle, adding volume with fillers comes with the inherent risk of product aggregation and the Tyndall effect. Hyaluronic acid (HA) fillers are currently the most commonly used product for infraorbital volume loss correction.6 Other products used for the treatment of the infraorbital area include calcium hydroxyapatite and Poly-L-lactic acid (PLLA).
Poly-L-lactic acid (PLLA) (Sculptra®, Galderma Laboratories, Fort Worth, TX) is a biostimulatory agent, currently FDA cleared for HIV lipoatrophy and correction of fine lines and wrinkles in the cheek area. Multiple studies have shown that it increases type I collagen production 3 to 6 months after injection. PLLA particles are mixed with sterile water, which is absorbed within a few hours of injection, leaving behind the PLLA molecules. The body recognizes PLLA as a foreign body and induces a subclinical macrophage-driven inflammatory reaction, which leads to fibroblast activation and increased collagen synthesis.7 PLLA has numerous off-label indications and is commonly used to address both volume loss and skin
